While this particular model with all its features is not illustrated in either the 1885 or 1903 Seibert calatogs, it conforms to the middle polarizing model IIb described in the 1903 catalog with the analyzing prism mounted in the tube, but with the addition of a Bertrand lens. It features a substage polarizing condenser with a removable top element that is focused using a lever mechanism, an analyzing prism mounted in the tube in a slide-in holder, a centerable rotating stage with calibrations in degrees with venier, and a focusing slot which holds a Bertrand lens. An additional slot is provided that accomodates the compensator plates; two are provided. In addition, it comes with two Seibert objectives, two eyepieces, and for conventional microscopy, an aperture stop holder with three stops. Another, less complicated, polarizing microscope of similar vintage is also represented in the collection.